Posting here with any regularity continues to be difficult; the gaps pretty much coincide with the arrival of marking, and last for as long as it does. None of this is reducing the queue of things I want to talk about, but this post will at least get something out of it. I’ve been meaning to write something about this particular source for three years or so, since my second semester here at Leeds in which I found myself the convenor of an old module that I still run, called ‘Empire and Aftermath: The Mediterranean World from the Second to the Eighth Centuries’. This is more or less a late antique survey of essentially political content, with some pauses to consider other issues, and one of these other issues is the venerable Pirenne thesis, the argument of the early twentieth-century historian of towns Henri Pirenne that despite its political breakdown the Roman world remained an economic and cultural unit until the rise of Islam cut northern and western shores of the Mediterrean off from eastern and southern and ended the commerce on which the whole thing ran.1 I used to worry about teaching the Pirenne thesis, because it seemed to me like a dead debate and I think focusing on those artificially is a bad illustration to students of what we do, but a recent article by Bonnie Effros has revived it somewhat or, at least, shown why it’s still current, and coincidentally makes a great key secondary reading! But the question I was faced with was what to use as a primary source. How do you show a class with no foreign languages a large-scale economy over the course of a century from which there’s very little relevant written evidence?
Sixth-century imported kitchenwares on display a few stories above the rubbish pits in which they were found in the Crypta Balbi, Rome, photo by yours truly. I have honestly thought of compiling these photos, dodgy though they are, and transcriptions of the museum captions into a source-pack, but thankfully have so far stopped myself. Why isn’t there such a write-up?
Obviously, you have to focus on a case study. My first thought was that I wanted a short clear piece of English writing about the ceramic deposit from the rubbish dump in the Crypta Balbi in Rome, which dramatically shrank then stopped over the seventh century. As far as I can see, though, there isn’t such a piece of writing: I could find use of it as an explanation of stratigraphy in a two-page appendix on ceramics in the period in general, or else just diagrams, and everything else is in Italian.2 I even asked someone knowledgeable at the British School of Rome and the best they could suggest was the museum guidebooks, which I duly ordered and were, alas, no use at all for my purposes.3 (The photos came later, and I’ll tell that tale in due course.) So, in the first year I went with the list of travellers from the appendices of Michael McCormick’s Origins of the European Economy, but they’re almost impossible to understand out of the context of the book.4 Next year, inspired by a then-recent paper of Chris Wickham’s, I used the letters of Pope Gregory the Great that talk incidentally about Mediterranean shipping, but that wasn’t ideal either because Gregory was pre-Islamic, so could only show a before, not an after.5 Now I use a charter supposedly issued by King Chilperic II about tolls on shipping at Marseille, and that sort of works, but it took me a while to find it and it’s still not quite ideal because of its complex textual history and some dubious features.6 But this post is about none of these things—though any suggestions and comments would be most welcome—but something I found while looking. (Pirenne does come back at the end, though, there is a plan of sort at work here, honestly.)
This is not the right charter of Chilperic II, but it does do some of the same things; this is a grant to St-Denis from 716 that survives as Paris, Archives nationales, K3/17, image from ARTEM via Wikimedia Commons
If you are a teaching medievalist, or even just a determined enthusiast, you will of course be familiar with that marvellous phenomenon, the old source reader. While either Patrick Geary’s or Barbara Rosenwein’s big newer ones serve teaching purposes very well, the tradition in which they stand is a very long one.7 If you’ve really looked at the Internet Medieval Sourcebook you may have noticed quite how much of it has names like Henderson, Thatcher, Ogg and so on attached to it, and to be honest while he’s added to the basic corpus, so does Geary’s in many places, and so indeed does pretty much every other modern anthology I’ve used.8 And while the commonest ones are all from the early twentieth-century USA and carry pretty much the same basic content, with a religious and constitutional focus unsurprisingly enough, when you start poking around not only does each of them have one or two things in that only their translators thought were interesting, but also there are some specialist ones constructed because of that thematic focus, these usually being economic.9 And in those latter there’s some really interesting stuff, things that not only have people not translated but which not that many people know exists.10 At least, I didn’t (which I realise is not the same thing). And this post, he finally announces three paragraphs down, is about one of those.
Cover of Robert S. Lopez and Irving W. Raymond (edd./transl.), Medieval Trade in the Mediterranean World
The anthology in question is about medieval trade, and like most sourcebooks it’s out to provide documentation for a historical argument—I guess they all are, really, if one accepts that ‘these are the roots of our culture and liberties’ is an argument. That argument is the one of the so-called Commercial Revolution, and accordingly the sourcebook is by the man who came up with that, Robert Lopez, along with some help from one Irving W. Raymond.11 And while the things you’d expect to be there—bits of Genizah documentation, letters from Genoa and so on—are here, so is some really interesting other stuff. I was going to do a run of From the Sources posts about these, but then remembered that because there is a second edition of this book, updated by the late lamented Olivia Remie Constable, they’re all still under copyright.12 So you can’t have the Lombard slave sale I thought was such a clear example of people-dealing in the early Middle Ages, but I do want to say something about what Lopez and Woodworth bill as ‘Regulations from the Royal Court at Pavia’.13 I can’t give it you in full translation, because as I say what Lopez and Raymond gave of it is protected by law, but they didn’t use all of it, so I can give you the rest, and when you have that it starts to look like quite a different, and fascinating, but awkward, source. So, here are some rules that someone in Pavia wanted written down, with the bits that Lopez and Raymond covered in square-bracketed summary with references.14 As ever this translation is fast and could probably be improved, but I hope it’s accurate enough to justify the argument I’m going to pull from it.
“In the name of our Lord Jesus Christ, ever-eternal God. These institutes of the kings of the Lombards, these royal fasces, these honours of this ancient city of Ticinum should be fixed in solid white marble, lest long age should anywhere succeed in abolishing them. This city, the first to hear Christian words and on this account blessed with the Lord among other cities, Saint Syrus did bless at the beginning of his introduction and said: ‘O blessed city, read! No little, but greatly and copiously shall you be called upon within the limits of cities among other towns, praise shall come to thee from the furthest mountains.’ Rome named Pavia and called it her daughter. And just as Rome crowns the emperor in the church of San Pietro with her pope, so does Pavia with her bishop crown the king in the church of San Michaele Maggiore, where there is one round stone with four other round stones. The royal palace is in this city of Pavia, to which and to the royal presence therein are bound to and should come all the princes of Italy, for so fortune stirred up from the deeds of Ausonia councils to be celebrated with mature deliberation and whatever should have been deliberated in the said council to be observed under the beneficence of the king. For Pavia ought to have counts of the palace, who should hold audiences or courts of law for the whole of Italy in every place as if it were before the emperor and to do justice unto everyone; and she should have a missus of the king, and he should resolve disputes throughout Italy according to precept. Pavia should have a royal advocate and palatine judges. Moreover all the judges of Italy should settle cases by sentence. For they used to come to the general school of this blessed city of Pavia from all the cities of Italy to study in the civil law and to learn the laws, and the best and most honoured were the judges of Pavia. The bishops of Pavia stand out from all the cities of Italy. From all the priests of the church of San Siro, from all the clergy who were of this city, there were vouchsafed many divine graces and blessings.
- “All of you whom touch the love, utility and honour of the kingdom of Lombardy, hear with light and equable spirits, how all of the duties that pertain to the royal chamber and palace and all the royal rights of the Lombards were instituted in ancient times!”
- [Merchants entering the kingdom paid a tenth of most sorts of produce (horses, slaves, cloth, some metals) at any (maybe all?) of a range of listed toll stations; pilgrims to Rome are exempt.15]
- [Anglo-Saxon merchants were also exempt, because they raised so much trouble and complaints that a treaty was brokered by which their king sent a load of luxury goods (silver, dogs (wearing silver), cloaks (probably silver-embroidered…), shields and so on) to the Lombard king every year instead.16]
- [Venice had a similar arrangement by which fifty pounds of silver deniers annually and a big cloak buys their merchants free access to all Lombard ports.17]
- [Despite that, Venetian merchants coming to actual Pavia paid every fortieth solidus they carried to the monastery of San Martino there, and a delegation from Venice still brings the royal treasurer a pound of pepper, one of cinnamon, one of galanghal and one of ginger annually, plus a comb and mirror or twenty deniers for his wife.18]
- [Salerno, Gaeta and Amalfi had the same deal for access to Pavia.19]
- [Pavia’s own merchants carry an imperial safe conduct which should get them trouble-free access to all markets in Italy, on pain of a payment of 1,000 mancuses.20]
- [Pavia’s mint is farmed out to nine masters each year, who are in charge of the moneyers and pay 12 pounds each to the royal treasury annually for the privilege, and another four to the count of the palace; they are to cut off the right hand of any moneyer making false coin.21]
- [Milan can make coins on the same standard as Pavia as long as they pay twelve pounds of them to the royal treasury in Pavia every year; the same rules about forgers apply.22]
- “Also there are all the gold-panners who send a levy to Pavia, and they never ought to sell gold to anyone under oath, and they ought to consign it to [the king] and the chamberlain. And they ought to buy all that gold at a rate of two solidi, that is an eighth of an ounce, that is two and a half deniers, for sixteen solidi, that is eleven ounces, in the rivers where they pan for gold, which are these: Padus, Ticinus, Dorica, Sicida, Stura, Misturla, Octo, Amalone and Amalona, Celo, Duria, Blavum, Urba, Salvus, Sesedia, Burmia, Agonia, Ticinus from the Great Lake that runs into Padua. There are also these rivers: Abdua, Oglius, Mentius, Sarno, Adexe, Brenta, Trebia. And they ought to pan for gold in all the other rivers aforesaid.
- “There are moreover fishermen in Pavia, who should fund one master from all their goods, and they should have sixty ships, and for each one of the ships they ought to give two denari every Kalends; the which kalendular denari they should give to their master, and they ought to make such savings that, when the king is in Pavia, they may use those denari to buy fish and at the same time bring them honourably daily to the court and to give fish to the chamberlain every Friday.
- “There are also twelve tanners, makers of hides, with twelve juniors, and they should make twelve of their hides from the best cows every year and give them to the royal chamber, so that no [other] man be allowed to make hides. And whoever infringes this, let him pay a hundred Pavian soldi to the royal chamber. And when any one of these tanners first enters, the greater ones ought to give four pounds, half to the royal chamber and half to the other tanners.”
- [The local boatmen and shipowners also appoint masters, from whom the king and queen each have pre-emption of one ship when they are in Pavia, along with a smaller pilot vessel to clear their passage, all of whose expenses are borne by the court.23]
- “And there were soapmakers in Pavia, who used to make soap, and who gave a render every year to the royal chamber of a hundred pounds of soap, and ten pounds of soap to the chamberlain, so that no-one else should make soap in Pavia.
- There is also a custom with those women, who are rich, but who do not have tutors or guardians, and who wish to marry, that they should come and entreat the chamberlain, so that he may act for god and for the soul of the king, and give them a tutor or guardian and license to marry whom they wish, according to his law; and that woman ought to offer there a best-quality shield and lance, to give to the chamberlain.
- “There is moreover in the church of San Siro a brass lamp, where the chamberlain ought thrice yearly, at Christmas, Easter and Pentecost, for each one of those festivals, to give a pound of Pavian denari in oil, so that that lamp may be filled and lit for the soul of the king. And the twelve retainers who are wardens in the church of San Siro, ought each one to receive linen clothes and each one a pair of boots and at Easter each one a cloak and cord shoes, so that they guard the emperor’s light well; and as many times as the king enters the church of San Siro in procession, thus he ought to give to those same twelve retainers every year for the king’s soul, so that God may answer their prayers. And two of the retainers of San Michaele Maggiore should receive clothes, just as do the retainers of San Siro.”
- [No-one is allowed to undertake any of these roles without license from the court, on pain of the bann, and Pavia’s merchants always get first choice in the markets here.24]
Lopez and Raymond stopped there, but actually there’s a load more, and it’s metaphorical gold:
- “And the abovesaid men, who hold these duties, which are written above, ought not to arrange or hold any meeting except before the king or the chamberlain.
- “And of all these duties, which are written above, the tenth part belongs to the royal chamber, as a benefice, note, the tenth as a benefice of the king, and from all those same duties that pertain to the king, his wife the queen ought to have the third part.
- “Know you this, that Gisulf the chamberlain, who was noble and rich, received all those same duties with all honour in the time of King Hugh and his son King Lothar, husband of Adelaide, and in the time of the first King Berengar and in the time of the first Emperor Otto. Once that Emperor Otto was dead, that Gisulf held the chamberlain’s office and his son Ayrald held it after him with all honour, just as did his father, up till the second and third Emperors Otto. With Ayrald the chamberlain having died, Agisulf his son ought to hold the chamberlain’s office, just as his father did.
- “Then there came that devil who is named John the Greek, who was a very apostate and a heretic, the Bishop of Piacenza, and he was a counsellor of the Greek empress and her son the third Emperor Otto, who was a child, and the king bestowed all those same duties on John the Greek, and he wanted to hold all those same duties which belonged to the royal chamber in his own hand. And he emplaced two of the Greek empress’s slaves, one of them named Siccus and the other Nanus, and gave them all those duties that are written above. And then that accursed John the Greek did not know the difference between the honours of the chamber and the profits of the royal chamber. And then that John and the bad ministers of the Greek empress with her son Otto, who was a child king and a young man, began to put the royal duties up for sale and to give them out in perpetuity and to disperse all those same duties, and those same duties were never afterwards honourable. And Emperor Henry sold many duties, which, since he had no son, the chamber should have inherited as a royal honour. And if he had been a prudent and honourable emperor, such as the empire should have, he would have had all those grants that have been made from these duties of the chamber cut up and the royal chamber assured of its status and permanence, just as it was from ancient times.
“All these honourable duties and very many others should be in Pavia, with the mercy of God and Holy Mary and Saint Syrus, who sends her bishops to Rome so that they ought to receive blessing and unction and consecration from the hand of the Pope. Just as the Apostle who raised the dead is in Rome, so there is Saint Syrus in Pavia who raised three men from the dead and gave sight back to a blind man, which we have never heard that any of the apostles did, and he did other beautiful and marvellous miracles too. In Rome there is one of the four doctors, Saint Gregory. In Pavia is another holy doctor, Augustine. Also by the mercy of God there was a bishop of Pavia who was from the apostolic see in Rome, who was called Peter by name. O glorious city of Pavia, endowed with a hundred and twenty-seven churches and sixteen monasteries, which are well staffed by night and by day and busy praying to the Lord, so that thou may always be saved with the men and women who are in thee, and with the animals and all the goods!”
You see, isn’t it more interesting when you know how it ends? So, let’s consider here. Lopez and Raymond billed this as “a nostalgic list of the rights and incomes lost by the royal treasury in Pavia”, and seamlessly stitch it together with a tale of burgeoning economic forces that made such royal control of trade impossible: the free market and the communes were coming, and tradition could not stand in their way!25 They offer it, therefore, as a source for what had once been, which apparently included royal trading treaties not unlike ones we’ve looked at here before and a variety of things we might reasonably call guilds, somewhat precociously. Predictably, as we can see, Lopez and Raymond were much more interested in anything that was sold or shipped than anything that was not, especially if it looked like royal throttling of free market exchange; their story was of the triumph of the market. But once you have the coda, it’s clear that that was not what the compilers thought was going on. I think, given how much he comes up, it is clear that those compilers were at the church of San Siro, and it looks rather as if they had somehow wound up either inheriting or championing the claim of the would-be third-generation chamberlain Agisulf to whatever rights they themselves didn’t get, which is why we have this odd mish-mash of commercial and ecclesiastical prerogatives. Clearly, what they thought had happened is that a foreign regime with no respect for their rights had barged in and sold all the offices off. They were still out there, the duties were still being charged as far as we can tell; those sailors were probably still paying their denari, the fisherman were still likely piling up money for fish for the court and for all we know twelve really good hides were still dumped at the palace every year, but San Siro and Agisulf weren’t seeing the profits, and that was the real issue.
The Romanesque church of San Michele Maggiore di Pavia, as rebuilt at the end of the eleventh century, a fact that will shortly become significant! Image by Slawojar and licensed under Creative Commons via Wikimedia Commons
What does this mean for the source as used by Lopez and Raymond? Well, firstly it means that since the rights were no longer held by the people who claimed them, we can’t be sure that they all ever were. Presumably they did exist, or granting the claim would mean setting up new infrastructure to try and exact them, and there are other sources we’ve looked at here showing extensive market trade in tenth-century Pavia; but lots of these things might not actually have been effective royal claims. For Lopez and Raymond that maybe didn’t matter; as they said, “it commemorates a regime that was already doomed as the document was drafted”.26 And they may have been right about that, but they were also wrong, or (since Lopez knew his Italian history) more likely quietly misleading, about why it was doomed.
Byantine ivory showing Christ crowning Emperor Otto II and Theophanu in 982, Paris, Musée de Cluny, image by Clio20, licensed under Creative Commons via Wikimedia Commons
The deeper context here, you see, is not economic at all.27 As the source says, Otto III succeeded as a child after his father’s untimely death in 997, and his mother, the Byzantine princess Theophanu, became regent. Perhaps, indeed, she and her cronies didn’t understand how great and magnificent Pavia was supposed to be—from the beginning and end of the source it seems like maybe no-one really can understand this enough. But the problem was not that they gave in to market forces and the clamouring demand for capitalist liquidity; it’s that they didn’t hold court at Pavia. In fact, no-one had done that with any regularity for quite a while. Hugh and Berengar I did, but kings from over the Alps then became Kings of Italy as well as Kings of the Germans with the Ottonian takeover, and obviously then they weren’t there as much. Otto III actually set up in Rome (whose apostles, as we are told here, aren’t a patch on Saint Syrus) and Henry II was barely in Italy at all. Furthermore, when he first came, it was provoked by the need to remove from it a new local king, Arduin, who had been crowned guess where? In Pavia, in San Michaele Maggiore to whose churchwardens the king should be giving fresh linen three times a year but which was actually at this point lying partly ruined after its destruction in 1004, hence the Romanesque rebuild shown above! (You’ll notice there’s no mention of that, or of Arduin, in our source…)
I mean, you can see he had his hands full… Coronation image from Henry II’s own sacramentary, now München, Bayerische Staatsbibliothek, Clm 4456, fol. 33, image public domain via Wikimedia Commons
So Henry was understandably not friendly with the royal city of the Lombards and in any case, he was largely busy elsewhere. Pavia had just ceased to be a major royal centre. The king or emperor didn’t come and eat the fish any more, no-one needed the hides; even the Anglo-Saxon silver, if it was still being sent, was presumably being sent somewhere else. The disconnection and disenfranchisement of the old capital would become such that, as very very long-term readers may remember or else maybe you already know, in 1037 the citizens would actually burn the palace and then claim, when called to account for it, that since there had been no king at the time there was no blame attached to such actions. King Conrad II thought otherwise, and in so judging sort of invented the idea of the king’s two bodies, but that would be a story for another time.28 The thing is, it wasn’t economic change that had made a backwater out of Pavia, it was good old-fashioned royal dynastic politics. Lopez’s Commercial Revolution has quietly stood the test of time nearly as long as Pirenne’s thesis with which we began this post (remember?), but it’s things like this that make me wonder whether, if we poked it, it would begin to come apart in the same way. It makes you wonder why no-one has tried, doesn’t it…?
1. Referring of course to Henri Pirenne, Mohammed and Charlemagne, trans. Bernard Miall (London 1939). For historiography on it (huge!) see Bonnie Effros, “The Enduring Attraction of the Pirenne Thesis” in Speculum Vol. 92 (Cambridge MA 2017), pp. 184–208, with many many references.
2. Stratigraphy training: Olof Brandt, “Interpreting the Archaeological Record” in Philip Rousseau (ed.), A Companion to Late Antiquity (Oxford 2009), online here, pp. 156-169 at pp. 160-161; diagrams in Simon Loseby, “The Mediterranean Economy” in Paul Fouracre (ed.), The New Cambridge Medieval History volume I: c. 500‒c. 700 (Cambridge 2005), pp. 605–638 at p. 609. I think the Italian work of reference would be Daniele Manacorda, Lidia Parola & Alessandra Molinari, “Diletta Romei: la ceramica medioevale di Roma nella stratigrafia della Crypta Balbi” in La ceramica medievale nel Mediterraneo occidentale: (Atti III Congresso Internazionale della Università degli Studi di Siena) (Firenze 1986), pp. 511-544, but I will admit I haven’t read it.
3. I got Daniele Manacorda, “Excavations in the Crypta Balbi, Rome: a survey” in Accordia Research Papers Vol. 1 (Firenze 1990), pp. 73–81 and Daniele Manacorda et al., Crypta Balbi: Museo nazionale romano. English edition, trans. Joanne Berry and Nigel Pollard (Milano 2000), but while both are good, I was after something quite specific.
4. Michael McCormick, Origins of the European Economy: Communications and Commerce, A. D. 300-900 (Cambridge: Cambridge University Press, 2001), pp. 799-810.
5. Now best found, despite some reservations, as John R. C. Martyn (trans.), The Letters of Gregory the Great, translated, with introduction and notes, 3 vols (Turnhout: Brepols, 2004).
6. Theo Kölzer, Martina Hartmann and Andrea Stieldorf (edd.), Die Urkunden der Merowinger, Monumenta Germaniae Historica (Diplomata regum ex stirpe merowingicarum) (Hannover 2001), 2 vols, I doc. no. 171.
7. These days available as Patrick J. Geary (ed./transl.), Readings in Medieval History, 5th edn. (Toronto 2016) and Barbara H. Rosenwein (ed./transl.), Reading the Middle Ages: Sources from Europe, Byzantium and the Islamic World (Toronto 2014), so Toronto profit whichever you buy!
8. Referring respectively to Ernest F. Henderson (ed./transl.), Select Historical Documents of the Middle Ages (London 1903, many reprints), online here; Oliver J. Thatcher and Edgar Holmes MacNeal (edd./transl.), A Source Book for Mediæval History: Selected Documents illustrating the History of Europe in the Middle Age (New York 1905), online here; and Frederic Austin Ogg (ed./transl.), A Source Book of Mediæval History: documents illustrative of European life and institutions from the German invasions to the Renaissance (New York 1907), online here.
9. The one of these I’m not using here, hard to get hold of but very interesting, is Roy C. Cave and Herbert H. Coulson (edd./transl.), A Source Book for Medieval Economic History (New York 1965).
10. Though none of them seem to contain the Raffelstetten Inquest. Why not? You’ll just have to carry on getting it here I guess…
11. Robert S. Lopez & Irving W. Raymond (edd./transl.), Medieval Trade in the Mediterranean World: Illustrative Documents Translated with an Introduction and Notes (New York 1967). From this would soon come Robert S. Lopez, The Commercial Revolution of the Middle Ages, 950–1350 (New York 1971), which is therefore I suppose an example of teaching-led research.
12. Robert S. Lopez, Irving W. Raymond & Olivia Remie Constable (edd./transl.), Medieval Trade in the Mediterranean World: Illustrative Documents Translated with an Introduction and Notes, 2nd edn. (New York 2001).
13. Leeds only has the first edition, so the following cites all come from Lopez & Raymond, Medieval Trade, not Lopez, Raymond & Constable. In that first edition the slave sale is doc. 13, pp. 45-46, a Lombard sale of a “boy from the Gallic people”. The “Regulations” are doc. 20, pp. 56-60.
14. The Latin can be found in A. Hofmeister (ed.), “Institvta regalia et ministeria camerae regvm longobardorvm et Honorantiae civitatis papiae” in H. Kaufmann, Hofmeister, G. Leidinger, W. Levison, G. Smidt & E. Assman, Monumenta Germaniae Historica, Scriptores in folio XXX.3 (Leipzig 1934), pp. 1444-1460, online here.
15. Lopez & Raymond, Medieval Trade, doc. 20 at pp. 56-57.
16. Ibid., pp. 57-58.
17. Ibid., p. 58.
18. Ibid.. I have to admit that this seems very very early to me for galanghal to be coming west, which might make us want to ask about the fourteenth-century preservation of this apparently-eleventh-century text (acknowledged Lopez & Raymond, Medieval Trade, p. 56 n. 26). But I’m not going to ask about it now, because this post is already a massive monster…
19. Ibid., pp. 58-59.
20. Ibid., p. 59.
22. Ibid., pp. 59-60.
23. Ibid., p. 60.
25. Ibid., p. 56, inc.: “The new economic forces help the bishops undermine the power of the emperor and king, but at the same time they also prepare the future downfall of both bishops and imperial officials and the victory of the free Commune.”
27. For what follows see most simply Guiseppe Sergi, “The Kingdom of Italy” in Timothy Reuter (ed.), The New Cambridge Medieval History volume III: c. 900–c. 1024 (Cambridge, 1999), pp. 346–371, and more deeply Giovanni Tabacco, The Struggle for Power in Medieval Italy: structures of political rule, transl. Rosalind Brown Jensen (Cambridge 1989), pp. 144-222.
28. For this, as well as Tabacco, I’d still cite Hagen Keller, “Das Edictum de beneficiis Konrads II. und die Entwicklung des Lehnswesens in der erste Häfte des 11. Jahrhunderts”, in Il Feudalismo nell’alto Medioevo, Settimane di Studio del Centro Italiano di Studi sull’Alto Medioevo Vol. 47 (Spoleto 2000), I pp. 227-261, though I realise that that’s not a massively helpful reference to the casual enquirer.